There are two questions that need to be answered here. Let's address the first one here:
How many bags will Eva need to make both pieces?
She needs 13/10 lbs. There are 8/10 lbs per bag. She would use 1 5/10 bags, but since they are bags, you would say 2.
Now, the second question:
How many pounds are left over?
She started with 3x8/10=2.4 lbs
We take away what she used: 2.4-1.5=0.9
There will be 0.9 lbs left over.